As Norm mentioned, George Thomas did some experimenting and wrote several paragraphs in his book on the results of different geometries. I believe the last iteration he mentioned had the V-groove in the top edge, and a convex V on the front edge. That is, instead of being flat on the cutting end, it had a shallow point(another 140 degrees). One beneficial effect of this is to make the geometry of the two outer corners a little more substantial so they don't break down as quickly.
"In theory there’s no difference between theory and practice. In practice there’s a lot of difference.” Yogi Berra